Trouble connecting Pixhawk to Mission Planner through TCP or UDP

Hello all,

I’ve setup raspberry pi to connect to 4G and connect pixhawk to Mission Planner over 4G. It works flawlessly when I power the raspberry pi 4 to outlet, and power the pixhawk with a battery. I’m able to connect to Mission Planner with TCP or UDP. However, I connected the battery to 2 BECs. 1 powers the pixhawk and 1 powers raspberry pi (RPI). RPI connects to internet, I’m able to access the ardupilot website (RPI’s IP address). In system info, Baudrate shows: Not in use, Mavlink count shows numbers, but I cannot connect to Mission Planner or QGC. I’m able to stream the video from RPI, but I cannot connect to Mission Planner. Please let know if anyone has any idea why it’s happening.